An arrangement in which a first operating arm pivots in response to a rotor being pivoted from a neutral position in the forward direction by means of a legitimate mechanical key, locking of a lock part of a first opening/closing door thereby being released, and a second operating arm pivots in response to the rotor being pivoted from the neutral position in the reverse direction by means of a legitimate mechanical key, locking of a lock part of a second opening/closing door thereby being released is known from Patent Document 1, and in this arrangement first and second engagement steps are provided at an interval of 180 degrees from each other on the outer periphery of a shaft part coaxially and integrally provided with the rotor, the first operating arm is provided with an engagement projection that engages with the first engagement step when the shaft part rotates forward and a first fitting hole into which the shaft part is fitted with play so as to allow relative rotation of the shaft part in the reverse direction, the second operating arm is provided with an engagement projection that engages with the second engagement step when the shaft part rotates in reverse and a second fitting hole into which the shaft part is fitted with play so as to allow relative rotation of the shaft part in the forward direction, and a spring urging the rotor to the neutral position is provided between the cylinder body and the rotor.